%%%-------------------------------------------------------------------
%%% File : mod_sip_proxy.erl
%%% Author : Evgeny Khramtsov <ekhramtsov@process-one.net>
%%% Purpose :
%%% Created : 21 Apr 2014 by Evgeny Khramtsov <ekhramtsov@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2014-2022 ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program is distributed in the hope that it will be useful,
%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License along
%%% with this program; if not, write to the Free Software Foundation, Inc.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%-------------------------------------------------------------------
-module(mod_sip_proxy).
-ifndef(SIP).
-export([]).
-else.
-behaviour(p1_fsm).
%% API
-export([start/2, start_link/2, route/3, route/4]).
-export([init/1, wait_for_request/2,
wait_for_response/2, handle_event/3,
handle_sync_event/4, handle_info/3, terminate/3,
code_change/4]).
-include("logger.hrl").
-include_lib("esip/include/esip.hrl").
-define(SIGN_LIFETIME, 300). %% in seconds.
-record(state, {host = <<"">> :: binary(),
opts = [] :: [{certfile, binary()}],
orig_trid,
responses = [] :: [#sip{}],
tr_ids = [] :: list(),
orig_req = #sip{} :: #sip{}}).
%%%===================================================================
%%% API
%%%===================================================================
start(LServer, Opts) ->
supervisor:start_child(mod_sip_proxy_sup, [LServer, Opts]).
start_link(LServer, Opts) ->
p1_fsm:start_link(?MODULE, [LServer, Opts], []).
route(SIPMsg, _SIPSock, TrID, Pid) ->
p1_fsm:send_event(Pid, {SIPMsg, TrID}).
route(#sip{hdrs = Hdrs} = Req, LServer, Opts) ->
case proplists:get_bool(authenticated, Opts) of
true ->
route_statelessly(Req, LServer, Opts);
false ->
ConfiguredRRoute = get_configured_record_route(LServer),
case esip:get_hdrs('route', Hdrs) of
[{_, URI, _}|_] ->
case cmp_uri(URI, ConfiguredRRoute) of
true ->
case is_signed_by_me(URI#uri.user, Hdrs) of
true ->
route_statelessly(Req, LServer, Opts);
false ->
error
end;
false ->
error
end;
[] ->
error
end
end.
route_statelessly(Req, LServer, Opts) ->
Req1 = prepare_request(LServer, Req),
case connect(Req1, add_certfile(LServer, Opts)) of
{ok, SIPSocketsWithURIs} ->
lists:foreach(
fun({SIPSocket, _URI}) ->
Req2 = add_via(SIPSocket, LServer, Req1),
esip:send(SIPSocket, Req2)
end, SIPSocketsWithURIs);
_ ->
error
end.
%%%===================================================================
%%% gen_fsm callbacks
%%%===================================================================
init([Host, Opts]) ->
Opts1 = add_certfile(Host, Opts),
{ok, wait_for_request, #state{opts = Opts1, host = Host}}.
wait_for_request({#sip{type = request} = Req, TrID}, State) ->
Opts = State#state.opts,
Req1 = prepare_request(State#state.host, Req),
case connect(Req1, Opts) of
{ok, SIPSocketsWithURIs} ->
NewState =
lists:foldl(
fun(_SIPSocketWithURI, {error, _} = Err) ->
Err;
({SIPSocket, URI}, #state{tr_ids = TrIDs} = AccState) ->
Req2 = add_record_route_and_set_uri(
URI, State#state.host, Req1),
Req3 = add_via(SIPSocket, State#state.host, Req2),
case esip:request(SIPSocket, Req3,
{?MODULE, route, [self()]}) of
{ok, ClientTrID} ->
NewTrIDs = [ClientTrID|TrIDs],
AccState#state{tr_ids = NewTrIDs};
Err ->
cancel_pending_transactions(AccState),
Err
end
end, State, SIPSocketsWithURIs),
case NewState of
{error, _} = Err ->
{Status, Reason} = esip:error_status(Err),
esip:reply(TrID, mod_sip:make_response(
Req, #sip{type = response,
status = Status,
reason = Reason})),
{stop, normal, State};
_ ->
{next_state, wait_for_response,
NewState#state{orig_req = Req, orig_trid = TrID}}
end;
{error, notfound} ->
esip:reply(TrID, mod_sip:make_response(
Req, #sip{type = response,
status = 480,
reason = esip:reason(480)})),
{stop, normal, State};
Err ->
{Status, Reason} = esip:error_status(Err),
esip:reply(TrID, mod_sip:make_response(
Req, #sip{type = response,
status = Status,
reason = Reason})),
{stop, normal, State}
end;
wait_for_request(_Event, State) ->
{next_state, wait_for_request, State}.
wait_for_response({#sip{method = <<"CANCEL">>, type = request}, _TrID}, State) ->
cancel_pending_transactions(State),
{next_state, wait_for_response, State};
wait_for_response({Resp, TrID},
#state{orig_req = #sip{method = Method} = Req} = State) ->
case Resp of
{error, timeout} when Method /= <<"INVITE">> ->
%% Absorb useless 408. See RFC4320
choose_best_response(State),
esip:stop_transaction(State#state.orig_trid),
{stop, normal, State};
{error, _} ->
{Status, Reason} = esip:error_status(Resp),
State1 = mark_transaction_as_complete(TrID, State),
SIPResp = mod_sip:make_response(Req,
#sip{type = response,
status = Status,
reason = Reason}),
State2 = collect_response(SIPResp, State1),
case State2#state.tr_ids of
[] ->
choose_best_response(State2),
{stop, normal, State2};
_ ->
{next_state, wait_for_response, State2}
end;
#sip{status = 100} ->
{next_state, wait_for_response, State};
#sip{status = Status} ->
{[_|Vias], NewHdrs} = esip:split_hdrs('via', Resp#sip.hdrs),
NewResp = case Vias of
[] ->
Resp#sip{hdrs = NewHdrs};
_ ->
Resp#sip{hdrs = [{'via', Vias}|NewHdrs]}
end,
if Status < 300 ->
esip:reply(State#state.orig_trid, NewResp);
true ->
ok
end,
State1 = if Status >= 200 ->
mark_transaction_as_complete(TrID, State);
true ->
State
end,
State2 = if Status >= 300 ->
collect_response(NewResp, State1);
true ->
State1
end,
if Status >= 600 ->
cancel_pending_transactions(State2);
true ->
ok
end,
case State2#state.tr_ids of
[] ->
choose_best_response(State2),
{stop, normal, State2};
_ ->
{next_state, wait_for_response, State2}
end
end;
wait_for_response(_Event, State) ->
{next_state, wait_for_response, State}.
handle_event(_Event, StateName, State) ->
{next_state, StateName, State}.
handle_sync_event(_Event, _From, StateName, State) ->
Reply = ok,
{reply, Reply, StateName, State}.
handle_info(_Info, StateName, State) ->
{next_state, StateName, State}.
terminate(_Reason, _StateName, _State) ->
ok.
code_change(_OldVsn, StateName, State, _Extra) ->
{ok, StateName, State}.
%%%===================================================================
%%% Internal functions
%%%===================================================================
connect(#sip{hdrs = Hdrs} = Req, Opts) ->
{_, ToURI, _} = esip:get_hdr('to', Hdrs),
case mod_sip:at_my_host(ToURI) of
true ->
LUser = jid:nodeprep(ToURI#uri.user),
LServer = jid:nameprep(ToURI#uri.host),
case mod_sip_registrar:find_sockets(LUser, LServer) of
[_|_] = SIPSocks ->
{ok, SIPSocks};
[] ->
{error, notfound}
end;
false ->
case esip:connect(Req, Opts) of
{ok, SIPSock} ->
{ok, [{SIPSock, Req#sip.uri}]};
{error, _} = Err ->
Err
end
end.
cancel_pending_transactions(State) ->
lists:foreach(fun esip:cancel/1, State#state.tr_ids).
add_certfile(LServer, Opts) ->
case ejabberd_pkix:get_certfile(LServer) of
{ok, CertFile} ->
[{certfile, CertFile}|Opts];
error ->
Opts
end.
add_via(#sip_socket{type = Transport}, LServer, #sip{hdrs = Hdrs} = Req) ->
ConfiguredVias = get_configured_vias(LServer),
{ViaHost, ViaPort} = proplists:get_value(
Transport, ConfiguredVias, {LServer, undefined}),
ViaTransport = case Transport of
tls -> <<"TLS">>;
tcp -> <<"TCP">>;
udp -> <<"UDP">>
end,
Via = #via{transport = ViaTransport,
host = ViaHost,
port = ViaPort,
params = [{<<"branch">>, esip:make_branch()}]},
Req#sip{hdrs = [{'via', [Via]}|Hdrs]}.
add_record_route_and_set_uri(URI, LServer, #sip{hdrs = Hdrs} = Req) ->
case is_request_within_dialog(Req) of
false ->
case need_record_route(LServer) of
true ->
RR_URI = get_configured_record_route(LServer),
TS = (integer_to_binary(erlang:system_time(second))),
Sign = make_sign(TS, Hdrs),
User = <<TS/binary, $-, Sign/binary>>,
NewRR_URI = RR_URI#uri{user = User},
Hdrs1 = [{'record-route', [{<<>>, NewRR_URI, []}]}|Hdrs],
Req#sip{uri = URI, hdrs = Hdrs1};
false ->
Req
end;
true ->
Req
end.
is_request_within_dialog(#sip{hdrs = Hdrs}) ->
{_, _, Params} = esip:get_hdr('to', Hdrs),
esip:has_param(<<"tag">>, Params).
need_record_route(LServer) ->
mod_sip_opt:always_record_route(LServer).
make_sign(TS, Hdrs) ->
{_, #uri{user = FUser, host = FServer}, FParams} = esip:get_hdr('from', Hdrs),
{_, #uri{user = TUser, host = TServer}, _} = esip:get_hdr('to', Hdrs),
LFUser = safe_nodeprep(FUser),
LTUser = safe_nodeprep(TUser),
LFServer = safe_nameprep(FServer),
LTServer = safe_nameprep(TServer),
FromTag = esip:get_param(<<"tag">>, FParams),
CallID = esip:get_hdr('call-id', Hdrs),
SharedKey = ejabberd_config:get_shared_key(),
str:sha([SharedKey, LFUser, LFServer, LTUser, LTServer,
FromTag, CallID, TS]).
is_signed_by_me(TS_Sign, Hdrs) ->
try
[TSBin, Sign] = str:tokens(TS_Sign, <<"-">>),
TS = (binary_to_integer(TSBin)),
NowTS = erlang:system_time(second),
true = (NowTS - TS) =< ?SIGN_LIFETIME,
Sign == make_sign(TSBin, Hdrs)
catch _:_ ->
false
end.
get_configured_vias(LServer) ->
mod_sip_opt:via(LServer).
get_configured_record_route(LServer) ->
mod_sip_opt:record_route(LServer).
get_configured_routes(LServer) ->
mod_sip_opt:routes(LServer).
mark_transaction_as_complete(TrID, State) ->
NewTrIDs = lists:delete(TrID, State#state.tr_ids),
State#state{tr_ids = NewTrIDs}.
collect_response(Resp, #state{responses = Resps} = State) ->
State#state{responses = [Resp|Resps]}.
choose_best_response(#state{responses = Responses} = State) ->
SortedResponses = lists:keysort(#sip.status, Responses),
case lists:filter(
fun(#sip{status = Status}) ->
Status >= 600
end, SortedResponses) of
[Resp|_] ->
esip:reply(State#state.orig_trid, Resp);
[] ->
case SortedResponses of
[Resp|_] ->
esip:reply(State#state.orig_trid, Resp);
[] ->
ok
end
end.
%% Just compare host part only.
cmp_uri(#uri{host = H1}, #uri{host = H2}) ->
jid:nameprep(H1) == jid:nameprep(H2).
is_my_route(URI, URIs) ->
lists:any(fun(U) -> cmp_uri(URI, U) end, URIs).
prepare_request(LServer, #sip{hdrs = Hdrs} = Req) ->
ConfiguredRRoute = get_configured_record_route(LServer),
ConfiguredRoutes = get_configured_routes(LServer),
Hdrs1 = lists:flatmap(
fun({Hdr, HdrList}) when Hdr == 'route';
Hdr == 'record-route' ->
case lists:filter(
fun({_, URI, _}) ->
not cmp_uri(URI, ConfiguredRRoute)
and not is_my_route(URI, ConfiguredRoutes)
end, HdrList) of
[] ->
[];
HdrList1 ->
[{Hdr, HdrList1}]
end;
(Hdr) ->
[Hdr]
end, Hdrs),
MF = esip:get_hdr('max-forwards', Hdrs1),
Hdrs2 = esip:set_hdr('max-forwards', MF-1, Hdrs1),
Hdrs3 = lists:filter(
fun({'proxy-authorization', {_, Params}}) ->
Realm = esip:unquote(esip:get_param(<<"realm">>, Params)),
not mod_sip:is_my_host(jid:nameprep(Realm));
(_) ->
true
end, Hdrs2),
Req#sip{hdrs = Hdrs3}.
safe_nodeprep(S) ->
case jid:nodeprep(S) of
error -> S;
S1 -> S1
end.
safe_nameprep(S) ->
case jid:nameprep(S) of
error -> S;
S1 -> S1
end.
-endif.
